questions about "Requesting a Pseudo-Terminal"

Do you have a question? Post it now! No Registration Necessary.  Now with pictures!

There are two sections of the SSH specs I have questions about.  The
first is Section 6.2: Request a Pseudo-Terminal:

The above link uses vt100 as an example TERM environment variable
value for SSH_MSG_CHANNEL_REQUEST.  PuTTY uses xterm.  What advantages
does xterm offer over vt100?

Also, according to the above link, "the dimension parameters are *only
informational" (emphasis mine).  In that case, why have them?

I did "cat test.txt" on a file which had the letter "a" repeated 100
times.  The terminal was an 80x24 one but instead of adding a "\n"
after the 79th "a" nothing happened.  This suggests that the above
link is correct when it says "the dimension parameters are *only*

Finally, I have another question about Section 6.5: Starting a Shell
or a Command:

Per that link, "only one of these requests can succeed per channel".
I can understand why "shell" should only have one
SSH_MSG_CHANNEL_REQUEST per channel but what about "exec"?  Why not
allow additional "exec" channel requests after SSH_MSG_CHANNEL_EOF is
received?  As is, there's really no point in doing something like
"cd .." via "exec" when it's just going to be undone when the channel
is closed.

Site Timeline